Currently, fix-sized binders or cover structure are available for certain types of binding applications. There are about 14 sizes of binder that are available to cover the full range of sizes from 1/16" to 2". In the past, users of these types of heat sensitive binders have had to order binders of a variety of sizes to anticipate future needs. Since there have been so many sizes, considerable space has been required for storing them. Furthermore, if one's needs changes due to unexpected events, the user would be either short of covers of right sizes or in possession of binders of wrong sizes, or both. Problems of these types have been rather serious for casual users of binders of cover structures of the type here under consideration.
As those familiar with the stationery arts are aware, sheets of paper, or the like, have been bound together at one edge through the medium of resilient adhesive. A well known example of this technique is seen in the typical "pad" of paper in which the individual sheets are sequentially usable and removable from the pad by physical disengagement from the adhesive. In such binding systems, the sheets have been physically clamped to provide a maximum compression adjacent the edge to be supplied with adhesive. With the clamped sheets thus positioned, an adhesive material has been similarly applied to pamphlets, books, and the like, utilizing apparatus designed to first stack the sheets in aligned condition and then rigidly clamp the sheets adjacent the edge to be glued. Many books have been bound utilizing such prior art systems. However, for typical office or home use, the apparatus envisaged for such binding procedures has been extremely expensive and has required relatively skilled personnel for its successful operation. In the main, bookbinding done under such circumstances has required large manufacturing facilities and has been done on a high-volume basis only. At the same time, means have continually been sought permitting simple edge-binding. Although simplifications have been attempted in the formerly employed clamping systems, continued research led to the development of the bookbinding systems disclosed in U.S. Pat. No. 3,973,787, for use in an ordinary office and home operation. FIGS. 1-4, and FIGS. 12, 13 and 15 among others show the state of the art prior to the development of the present invention. With the bookbinding system shown in U.S. Pat. No. 3,973,787 hot melt adhesive strips of the new type disclosed in this application were not known or previously employed.